Form and Function of Tandem Duplicate Small RNA Molecules in Shigella dysenteriae

描述(申请人提供)：志贺氏菌病是一种由志贺氏菌属细菌感染引起的几种腹泻性疾病，在世界各地仍然流行。志贺氏菌病的全球负担部分是由于缺乏预防感染的疫苗。 一种普遍安全和可用的抗生素方案来治疗感染。尽管使用小RNA分子(SRNA)作为基于RNA的抗志贺氏菌治疗的模型或靶点的潜力是有希望的，但缺乏对sRNA在控制志贺氏菌生理和发病机制中所起作用的全面了解。为了实现开发基于RNA的抗生素治疗志贺氏菌病的长期目标，一个必要的第一步是揭示sRNA在多大程度上控制志贺氏菌的生理和毒力。为此，本研究的总体目标是阐明新发现的重复sRNAs RyfA1和RyfA2在控制痢疾链霉菌的生理和发病机制中的作用。正在测试的中心假设是，RyfA1和RyfA2是在独特的环境条件下差异产生的，并通过调节不同的重叠基因组的表达来调节痢疾杆菌的毒力。这一假说将通过实现以下具体目标来验证：1)确定调节RyfA1和RyfA2产生的铁和温度响应因子；2)通过确定RyfA1和RyfA2的调控靶标来阐明RyfA1和RyfA2的功能；以及3)确定RyfA1和RyfA2单独和联合对痢疾链球菌毒力的影响。RyfA1和RyfA2重复sRNAs的系统表征将有助于回答志贺氏菌致病机理和细菌sRNAs领域的基本问题，有助于实现开发治疗志贺氏菌病的长期目标。这项拟议的研究提出了一个创新的假设，即两个序列同源性为95%且预测结构相同的sRNA分子具有非冗余功能。这一假设将使用标准的、对学生友好的、细菌遗传学和创新的高科技分析的平衡方法进行验证。学生参与拟议研究的每一步构成了创新培训计划的基础，该计划将为学生提供细菌发病机制和基于RNA的调控领域的实践经验。由此产生的技能和经验的结合将使学生很好地为病原菌、共生菌和真核系统中快速发展的核糖体调控领域做出贡献。

DESCRIPTION (provided by applicant): Shigellosis, a several diarrheal disease caused by infection with bacteria of the genus Shigella, remains endemic throughout the world. The global burden of shigellosis is due in part to the lack of a vaccine to prevent the infection and the lack of a universally safe and available antibiotic regimen to treat the infection. While the potential f using small RNA molecules (sRNAs) as models for, or targets of, RNA-based anti-Shigella therapeutics is promising, what is lacking is a comprehensive understanding of the role that sRNAs play in controlling Shigella physiology and pathogenesis. A necessary first step towards achieving the long-term goal of developing RNA-based antibiotics to treat shigellosis is to reveal the full extent to which sRNAs control the physiology and virulence of Shigella species. To this end, the overall objective of this study is to elucidate the role of newly identified duplicate sRNAs RyfA1 and RyfA2 in controlling the physiology and pathogenesis of S. dysenteriae. The central hypothesis being tested is that RyfA1 and RyfA2 are differentially produced under unique environmental conditions and modulate S. dysenteriae virulence by regulating the expression of distinct over-lapping sets of genes. This hypothesis will be tested by achieving the following specific aims: 1) identify the iron- and temperature-responsive factors regulating the production of RyfA1 and RyfA2; 2) elucidate the function of RyfA1 and RyfA2 by identifying the regulatory targets of each; and 3) determine the effect of RyfA1 and RyfA2, individually and in combination, on S. dysenteriae virulence. The proposed systematic characterization of duplicate sRNAs, RyfA1 and RyfA2, will contribute to answering fundamental questions in the fields of Shigella pathogenesis and bacterial sRNAs, contributions that will facilitate achievement of the long-term goal of developing therapeutics to treat shigellosis. The proposed study puts forth the innovative hypothesis that two sRNA molecules that share 95% sequence identity and a identical predicted structure have non-redundant functions. This hypothesis will be tested using a balanced approach of standard, student friendly, bacterial genetics and innovative high-tech assays. Student involvement in every step of the proposed study form the foundation of an innovative training program that will provide students with practical experience in the fields of bacterial pathogenesis and RNA-based regulation. The resulting combination of skills and experience will position students well to contribute to the rapidly advancing fields of ribo-regulation in pathogenic bacteria, commensal bacteria and eukaryotic systems.